1. Field of the Invention
The instant disclosure relates to a method for fabricating solid electrolytic capacitors; in particular, a method for improving fabrication of solid electrolytic capacitors.
2. Description of Related Art
As technology rapidly evolves in the semiconductor industry, the demand for products requiring the use of semiconductors as well as the development of a more advanced, sophisticated electronic components become increasingly high. Semiconductor technologies such as flip chip packaging technology, laminated substrate design, and passive components design have an indispensable position in the semiconductor industry.
Take flip chip or ball grid array package structure for example, chips are configured on and electrically connected to the surface of the packaging substrate which is aggregated and formed from multiple layers of patterned circuits, and insulating layers. The patterned circuits are made by etching via photolithography while an insulating layer is disposed between two neighboring patterned circuits. Furthermore, in order to obtain the desired electrical characteristics for the package substrate, the substrate is further arranged with passive components such as capacitors, inductors and resistors which may be electrically connected to the chips and other electronic components through internal wiring of the substrate.
Among passive components, capacitors are classified according to the type of electrolyte applied, and can generally be categorized into liquid electrolytic capacitors and solid electrolytic capacitors. While the life span of the former is determined by the drying time of the liquid electrolyte, the latter uses a solid electrolyte, therefore eliminating the danger of drying electrolyte and providing a longer capacitor life span.
Traditional surface mounted tantalum solid capacitors usually comprise anode elements made from tantalum powder. However, the tantalum powder in the anode element leads to a relatively high technical threshold. For example: in order to increase overall capacitance, small particle size is essential to increase the overall reactive surface and consequently, the capacitance.
However, smaller particle size of the tantalum powder requires additional processing efforts to achieve. Thus, the smaller the particle size is required, the more processing is required to produce the desired size, and as a result, increases the costs. In addition, tantalum particles of smaller size make permeation of the cathode agent more difficult. Furthermore, since only after high-temperature sintering will the tantalum powder be able to form the tantalum sintered bodies on a substrate, the high-temperature sintering process required in the fabrication of traditional surface mounted solid capacitor renders the entire fabrication process more complex.
Additionally, prior art illustrates a multi-layer micro-capacitor comprising a stacked structure of multiple metal layers and dielectric layers, thus facilitating the miniaturization of capacitors, thereby increasing the scope of applications. However, such a structure comes with a higher cost, a high probably of short-circuiting, and a plurality of complex processes during fabrication and assembly.
To address the above issues, the inventor strives via associated experience and research to present the instant disclosure, which can effectively improve the limitation described above.